The BIG Leak!

The theory that the accelerated expansion of the universe is caused by mysterious "dark energy" is being challenged by New York University physicist Georgi Dvali. He thinks there's just a gravity leak.

Scientists have known since the 1920s that the universe is expanding. In the late 1990s, they realized that it is expanding at an ever-increasing pace. At a loss to explain the stunning discovery, cosmologists blamed it on dark energy, a newly coined term to describe the mysterious antigravity force apparently pushing galaxies outward.

This repulsive, unknown force is believed to make up more than 70 percent of the mass-energy budget of the universe.

But the existence of dark energy is far from proven, and some researchers believe they and their colleagues simply don't understand gravity at larger scales. The gravitational pull between any two objects becomes less with distance. But in Dvali's view, it weakens more than standard theory predicts.

Dvali would modify the theory of gravity so that the universe becomes self-accelerating, eliminating the need for dark energy. He presented his work here earlier this month at the annual meeting of the American Association for the Advancement of Science (news - web sites).

Dvali borrows from string theory, which states that there are extra, hidden dimensions beyond the four we are familiar with: three directions and time. String theory suggests that gravitons -- hypothetical elementary particles transmitting gravitational forces -- can escape to other dimensions. Dvali says this would cause "leaks" in gravity over cosmic proportions, reducing gravitational pull at larger distances more than expected.

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I recently tried to wrap my mind around string theory with little success, but loved the "common man" term "leak" for the universe. The idea the Universe is leaking of all thing Gravity, was very interesting to me.

Fascinating. I've been reading/listening to Brian Greene's books, and he does a good job of describing string theory. This is a nice alteration to current theory and does, in a bizarre way, make sense.

So why doesn't energy from other universes leak into here? Or does it?

So why doesn't energy from other universes leak into here? Or does it?

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Having had a lesson on nuclear fission and fusion today, I see plenty of space for it to leak in/out. There seem to be a lot of 'tricks' where my teacher says anti-matter/dark matter literally enters the equation, or absords energy (goes to parallel universe), but it seemed that sometimes new masses popped up or their were inconsistensies in the masses before and after the fission (entering from parallel universe?).

Fascinating. I've been reading/listening to Brian Greene's books, and he does a good job of describing string theory. This is a nice alteration to current theory and does, in a bizarre way, make sense.

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His books are amazing. I just read his older one, "This Elegant Universe." All I can say is wow.

I have read Hawkings over and over trying to digest some of it, about all I can retain is the table of contents.

Like calling beatlejuice, when need to summon mongothegeek.

MONGO! MONGO! MONGO!

<me hits refresh to see if the great mongo is here yet.............>

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ROFL...

Guess thats a signs that I spend too much time on MR...

Sheesh try to work at work.

I personally have issues wrapping my mind around the 6 dimensions of string theory though one of them I think is only supposed to be a quanta wide so its an A or B state.

I read an article about the ever expanding Universe in Analog a couple of months back. They were studying the Hubble constant and trying to come up with a rate of increase in this mysterious repulsive force.

I can't remember the whole spiel but the idea was that the repulsive force might be increasing and the end result will be in a few million years that it will be more powerful than gravity on the local scale, and eventually after that more powerful than nuclear strong...

Fascinating. I've been reading/listening to Brian Greene's books, and he does a good job of describing string theory. This is a nice alteration to current theory and does, in a bizarre way, make sense.

So why doesn't energy from other universes leak into here? Or does it?

Click to expand...

Assuming that mass exists in the other ones it should.

Think about living in an apartment. You can hear noise from all of the neighbor apartments, and noise from yours escapes into theirs. If there is noone in the other apartments you still loose noise even though you don't gain any.

If there's one thing I've learned from the time I've spent studying quantum physics (and having friends that know even more explain it to me), its that nobody understands string theory. Nobody. Not a single person in the world. Not you, not me, not Stephen Hawkings, not the person that came up with it.

Think about living in an apartment. You can hear noise from all of the neighbor apartments, and noise from yours escapes into theirs. If there is noone in the other apartments you still loose noise even though you don't gain any.

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Brilliant, MongoTheGeek. That's an analogy that I can wrap my head around.
I've always been a bit interested in this area, but intimidated by my complete lack of knowledge. Sounds like I'll have to check out this Greene fellow.

If there's one thing I've learned from the time I've spent studying quantum physics (and having friends that know even more explain it to me), its that nobody understands string theory. Nobody. Not a single person in the world. Not you, not me, not Stephen Hawkings, not the person that came up with it.

On another point, this reminds me vaguely of Timeline.

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Are you sure that's not just another theory?

powermac666 said:

Brilliant, MongoTheGeek. That's an analogy that I can wrap my head around.

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